Air-compressor.



T- 0. PERRY.

AIR COMPRESSOR. APPLICATION PILBD SEPT. 9,1907.

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INVENTOR T. O. PERRY.

AIR COMPRESSOR. APYPLIGATIOK' FILED SBPT.9,1907.

'INVEIYTOR Patented Jul '6, 1909.

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UNITED STATES PATENT OFFICE.

THOMAS O. PERRY, OF CHICAGO, ILLINOIS.

AIR-COMPRESSOR.

To all whom it may concern:

Be it known that I, THOMAS O. PERRY, a citizen of the United States,residing at Chicago, in the county of Cook and. State of Illinois, haveinvented new and useful improve ments in Air-Compressors, of which thefollowing is a specification.

This invention relates to improvements in the packing of plungers forair compressors and pumps.

The main object of my invention is to provide an elastic plunger packingwhich will not leak 011 account of wear, and which will cause as littlefriction as possible.

These objects I attain by the. mechanism illustrated in the accompanyingdrawings, in which- Figure 1 is an exterior side view of the aircompressor and its supports in elevation; Fig. 2 is an exterior frontview of the air com pressor and its supports in elevation; Fig. 3 is aplan of the cap or head to the cylinder of the air compressor Fig. 4 isa sectional elevation of the air compressor in a plane indicated by thebroken lines t 4 on Figs. 3 and 5 Fig. 5 is a plan of the plungerpacking and accesso ries showing the plunger in section; and Fig. 6 isan enlarged plan of the plunger packing and accessories showing theplunger in section.

Similar letters refer to similar parts through out the several views.

The compressor cylinder E has exterior flanges both at its upper andlower ends. The cap U, is secured to the upper end of the cylinder byscrews entering the upper flange. Plunger, F, fits the interior ofcylinder, E, loosely, is closed at its upper end, protrudes from thelower end of the cylinder and carries at its lower extremity across-head, Gr. Plunger rods, G rigidly connect the crosshead with thedrive-head, G, which is adapted to reciprocate above the cap C, and isce trally connected to the actuating rod, 1". A supporting plate, A, issecured to the lower end of the pipe A, which is supposed to be fixedabove in connection with some form of motor adapted to actuate the rod,r. Supporting guide rods, (1*, pass loosely through the drive head andrigidly connect the cylinder cap, C, to the supporting late, A.

Surrounding the plunger ELDL drawn to the lower cylinder flange byscrews is a clamping ring, N, having an interior flange underneathloosely fitting the plunger, and inclosing together with the cylinderend. an annular Specification of Letters Patent.

Application filed September 9, 1907.

Patented July 6, 1909.

Serial No. 392,063.

packing space. An elastic cylindrical packing, Q, having an exteriorflange on its under side in close contact with the clz'nnping ringsurrounds and presses against the plunger within the annular space,which is thus tightly closed, communicating only with the interior ofthe cylinder. A packing ring, a, is interposed between the cylinder end.and exterior flange of the packing so that it binds the packing flangeby tightening the clamping screw. Between the upper portions of thepacking, Q, and packing ring, n, is a thin annular recess, adapted toreceive packing springs, g, which react between the packing ring and theelastic packing. These packing springs are preferably arranged in twoannular layers, one within the other, and each layer is made up ofseveral thin, flat spring sections. Four spring sections are shown ineach layer in Figs. 5 and 6. The spring sections are all under tension.In the outer layer the ends of the spring sections press outward againstthe packing ring, while their centers press inward against the ends ofthe spring sections in the inner layer, which in turn press against theclastic packing throughout their length by reason of their proper formbefore insertion and the superior stiffness of the outer springsections. These spring sections may all be nearly straight before beingsprung into the annular recess, or they maybe curved before insertion assuits best the tensions required when in place. The packing may be madeof leather or other yielding material. The upper side of the clampingring, N, its closely around an annular shoulder on the end of thecylinder of about the same external diameter as the packingr ing, it.The annular packing space is also adapted to receive other forms ofpacking such as are ordinarily used.

The cross-head, G, is not rigidly connected to the plunger, F, but ismerely guided loosely in its open lower end and is carried rigidly by atie rod, L, whose upper end connects with a safety valve, L, which seatsagainst and is guided in the upper closed head of the plunger. Apowerfulsafety spring, M, surrounding the tie rod, reacts between the closedhead of the plunger and the cross head so as to hold the safety valveclosed. The safety spring should have sufllcient tension to drive theplunger, without yielding, against any normal resistance, but isdesigned to yield. to abnormal resistance, such as might result fromaccidental clogging of the outlet or undue compression. of air, so as torelieve the excessive pressure by letting the safety valve open. A veryslight lifting of the safety valve lets compressed air pass sufficientlyto avoid dangerous pressure.

.In the cylinder head is a check valve, J, opening outward, covered by acap, 0, from which the outlet or delivery pipe, 0, rises. The intakevalve, II, opens inward and is carried by and rests against a hollowcage, C, which screws into the cylinder head to one side of the outlet.The guiding stem of the intake valve reaches up through the center ofthe cage and terminates in a knob, II, attached so as to form a shoulderbeneath which a helical spring, H coiled around the stem and resting ina recess of the cage reacts to balance the weight of the valve more orless. The under side of the knob, II, is guided in the recess and itsupper part is enlarged so as to limit the vertical movement of theintake valve. Around the pe riphery of the cage are openings for thepassage of air.

It should be noticed that the air pressure within the cylinder havingaccess past the plunger to the annular packing space acts to press thepacking against the plunger as well as against the clamping ring, andthis air pressure may sullice to make the packing suflicicntly tightwithout the aid of the packing springs or the packing ring aftercompression begins. But without the packing springs to close the packingtightly against the plunger before commencement of the compressionstroke, too much air might escape for want of initial tension. Thecombined pressure of the packing springs and compressed air against thepacking would cause considerable friction, if the pull on the packingdue to friction did not help to relieve the pressure against the plungerby reason of the pull of the plunger being directcd away from theclamped exterior flange of the elastic packing during the compressingstroke. Furthermore, the air pressure against the packing is materiallyreduced by reason of the very limited annular space between the plungerand the cylinder through which the air must pass to reach the annularpacking space. These considerations render waste of applied actuatingenergy due to plunger friction much less with this form of packing thanwith ordinary piston packings made of cup-shaped. leather.

What I claim as my invention, and. desire to secure by Letters Patent,is

1. In an air compressor, the combination with a plunger and a cylinderhaving closed and open ends, of an annular inclosure at the open end ofthe cylinder surrounding the plunger, a flexible annular packing closelysurrounding said plunger within said inclesure, and springs adapted toreact between the outer wall of said inclosure and said flexiblepacking, said springs being arranged in two annular concentric layers sothat the outer layer of springs presses the inner layer evenly againstall the sides of the packing, substantially as herein set forth.

2. In an air compressor, the combination with a plunger and a cylinderhaving open and closed ends, of a flexible annular packing closelysurrounding the plunger at the open end of the cylinder, and having anexterior packing flange, a packing ring interposed between the packingflange and the open end of the cylinder, a clamping ring adapted toclamp the packing flange against the packing ring, and springsinterposed and reacting between the packing ring and flexible packing soas to press the packing evenly against the plunger all around itsexterior, substantially as herein set forth.

3. In an air compressor, the eomoination with the plunger, and cylinderhaving open and closed ends, of a clamping ring adapted to close againstthe open end of said cylinder forming therewith around the plunger anannular packing space, a flexible annular packing within said packingspace adapted to press tightly around said plunger and against saidclamping ring, and packing springs within said annular space adapted topress said flexible packing inward against said plunger on. all sides,said annular packing space being adapted to receive and hold compressedair from the interior of the cylinder, substantially as herein setforth.

4. In an air compressor, the combination with the plunger, and cylinderhaving open and closed ends, of a clamping ring adapted to close againstthe open end of said cylinder forming therewith around the plunger anannular packing space, a flexible annular packing within said packingspace adapted to press tightly around said plunger and against saidclamping ring, a packing ring within said. packing space outside of saidflexible packing, and springs reacting between said. packing ring andsaid flexible packing adapted to press the latter inward against theplunger on all sides, said annular packing space bein adapted to receiveand hold compressed air from the interior of the cylinder, suostantiallyas herein set forth.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

THOMAS O. PERRY. lh itnesses Jas. A. TOWNSEND, G. R. BROWN.

